The increased world energy consumption and the environmental issues caused by exhaustive use of fossil fuel reiterate the need for developing a clean, renewable and economically viable energy alternative. The advantage of using hydrogen as fuel is based on its combustion without emitting pollutant gases in the atmosphere. The photoelectrochemical water reduction process is considered an interesting process because the photon energy is used to split the water to produce H2. A good photocatalyst used in this reaction must present good physical and chemical stability, low-cost production, low electron-hole recombination rate, and be abundant on Earth crust. Platinum is the most efficient catalyst for this reaction; however, it is an expensive and low abundant material, which makes its industrial application extremely limited. Ternary and quaternary chalcogenides are applied as absorber layers in highly efficient solar cells and they can be also applied to solar-to-hydrogen conversion. Chalcogenides photocathodes (chalcopyrite and kesterita) applied to hydrogen generation, typically are comprised by a CdS layer on the p-type semiconductor resulting in a p-n junction and it contributes to an efficient charge separation. Recently, MoS2 have been reported as a possible candidate to substitute CdS and Pt. Therefore, this proposal aims to develop and characterize chalcopyrite (CuInSe2 e CuInGaSe2) and kesterite (Cu2ZnSNSe4) containg a buffer layer formed by MoS2 and WS2, and the ones doped with Cu, Ni and Co. The films will be characterized by UV-Vis, X-ray diffraction, Raman spectroscopy. The efficiency of the materials wil be electrochemically evaluated by Tafel plots to determine overpotential and current density. The proposed materials for photocathodes will studied for the water reduction catalytic reaction for hydrogen evolution using a photoelectrochemical system.
News published in Agência FAPESP Newsletter about the scholarship: